You want to call plotIt from outside the module plotter. That is why jling said that plotIt is at Main.plotter.plotIt. So, basically, you’ve loaded the module plotter into the Main REPL, and plotIt is inside that.
To call it, use
julia> include("~/plotter.jl")
Main.plotter
julia> using .plotter # Load local module.
julia> plotter.plotIt(upwards)
Or, if you add export plotIt below the line module plotter, then you can use
...
julia> using .plotter
julia> plotIt(upwards)